The control and/or elimination of undesirable impurities and by-products from various manufacturing operations has gained considerable importance in view of the potential pollution such impurities and by-products may generate. One conventional approach for eliminating or at least reducing these pollutants is by oxidizing them via incineration. Incineration occurs when contaminated air containing sufficient oxygen is heated to a temperature high enough and for a sufficient length of time to convert the undesired compounds into harmless gases such as carbon dioxide and water vapor.
In view of the high cost of the fuel necessary to generate the required heat for incineration, it is advantageous to recover as much of the heat as possible. To that end, U.S. Pat. No. 3,870,474 (the disclosure of which is herein incorporated by reference) discloses a thermal regenerative oxidizer comprising three regenerators, two of which are in operation at any given time while the third receives a small purge of purified air to force out any untreated or contaminated air therefrom and discharges it into a combustion chamber where the contaminants are oxidized. Upon completion of a first cycle, the flow of contaminated air is reversed through the regenerator from which the purified air was previously discharged, in order to preheat the contaminated air during passage through the regenerator prior to its introduction into the combustion chamber. In this way, heat recovery is achieved.
U.S. Pat. No. 3,895,918 (the disclosure of which is herein incorporated by reference) discloses a thermal regeneration system in which a plurality of spaced, non-parallel heat-exchange beds are disposed toward the periphery of a central, high-temperature chamber. Exhaust gases from industrial processes are supplied to these beds, which are filled with heat-exchanging ceramic elements. Conventionally, the cold face of a regenerative oxidizer is constructed of a flat perforated plate supported by structural steel. The structural steel has typically been modified to allow air flow through the exchange bed, but the obstruction caused by the structural steel reduces the air flow uniformity through the exchange bed. Also, the flat perforated plate and structural steel must support the weight of the heat exchange media, and are subject to failure. This arrangement also creates a large volume below the heat exchange media which must be flushed before flow through the columns can be reversed.
It is therefore an object of the present invention to reduce or eliminate the weight bearing design of the cold face of a regenerative oxidizer, promote more uniform distribution of air, reduce the volume to be flushed and improve the effectiveness of the flushing.